1. Field of the Invention
The present invention relates to a process for the preparation of 2,3,5-collidine and 2-ethyl-5-methylpyridine. In particular, the present invention relates to a process for the preparation of 2,3,5-collidine and 2-ethyl-5-methylpyridine by reacting a carbonyl compound with ammonia in a gas phase in the presence of a catalyst.
2,3,5-Collidine and 2-ethyl-5-methylpyridine are useful compounds which are used in various applications such as raw materials of medicines and agrochemicals.
2. Prior Art
The following processes are known for the preparation of 2,3,5-collidine by reacting a carbonyl compound with ammonia in a gas phase in the presence of a catalyst:
a process comprising reacting methacrolein with ammonia in a gas phase in the presence of a catalyst which comprises silicon and a specific element such as zirconium, aluminum and/or phosphorus (see JP-A-8-245589), and PA1 a process comprising reacting methacrolein and methyl ethyl ketone with ammonia in a gas phase in the presence of an oxide catalyst comprising silicon, phosphorus and/or boron (see JP-A-8-259537).
However, the main product of the former process is 3,5-lutidine, while 2,3,5-collidine is obtained in a yield of only 16.5%. In the latter process, 2,3,5-collidine is obtained in a yield of 15 to 37%.
However, prior arts describe neither a gas phase catalytic reaction of a carbonyl compound and ammonia for the preparation of 2-ethyl-5-methylpyridine, nor the simultaneous preparation of 2,3,5-collidine and 2-ethyl-5-methylpyridine.